Phytoremediation of Mine Tailings Using Lolium Multiflorum

Abstract—In this research we studied the feasibility of applying phytoremediation in the mine tailings at La Concha site. The extraction efficiency of heavy metals was studied, as well as the tolerance to high pollution and biomass generation of Lolium multiflorum, known as Italian ryegrass, in the aggressive soils composed almost entirely by mine wastes. Ryegrass seeds were grown in mine tailings containing Cu, Mn, Zn, and Pb concentrations of around 800, 4600, 3200, and 5400 ppm respectively. Triplicate analyses of soils without treatment and with treatments consisting in organic matter (OM) additions were carried out during 90 days. Italian ryegrass has a high tolerance to polluted mine tailings, although the addition of small quantities of organic matter improves the extraction of metals. The highest metals uptake from tailings was achieved through treatment with 20 % OM additions, with varying efficiencies of around 50% for Zn and Pb in 90 days, although for Cu and Mn these were smaller, namely of 28 and 14% respectively. These results show that phytoremediation of mine tailings is possible through grass planting that was able to remove the heavy metals.